A clamping device as the one to which the present invention pertains is needed especially for rubber blanket cylinders and/or printing cylinders of rotary printing presses to fasten a rubber blanket or a flexible printing form, which is tensioned on a jacket surface of such a cylinder, on the cylinder while maintaining the tension. The cylinders have one or mostly a plurality of axial channels on their jacket surface, in which channel or channels a clamping device each is formed.
EP 0 856 401 A2 discloses an axial channel, which has channel walls that converge obliquely at an acute angle in relation to one another up to a channel opening on the jacket surface of the printing cylinder. A clamping body with lateral surfaces extending toward each other is arranged in the channel and tensioned in the direction of the channel opening, so that its two lateral surfaces are pressed against the channel walls converging at the same angle. A clamping gap is formed for the packing between one of the two channel walls and the lateral surfaces of the clamping body facing it. The clamping gap is set by means of bearing bodies, which are arranged adjustably at right angles to the clamping body.
Clamping devices that have clamping cams arranged pivotably in a channel of a printing cylinder are known from DE 195 09 561 A1 and DE 200 22 737 U1. The clamping cams are pivotable to and fro between a clamped position and a released position.
The prior-art clamping devices are not yet optimal especially in respect to their handling.
U.S. Pat. No. 5,010,818 discloses a clamping device that comprises a plurality of cylindrical clamping bodies, each of which is directly supported in an elastically nonrigid manner on a spring element in the radial direction of a printing cylinder. Even though the clamping bodies are movable in two non-parallel directions at right angles to an axis of rotation of the cylinder, partly due to the radial inward spring excursion of the spring elements and partly in the tangential direction of the cylinder, the movement in the tangential direction is associated with tilting and/or bending of the spring elements.
U.S. Pat. No. 5,123,353 discloses a clamping device with a clamping shaft, which is mounted movably on a mounting means of a pressing means against a force of elasticity generated by the pressing means. The clamping shaft has a regular cylindrical shape over part of its outer circumference and has a polygonal shape with either two or three flattened areas opposite the regular cylindrical part. It lies on the mounting means with its flattened areas. Depending on the number of flattened areas, it can assume two or three discrete angle of rotation positions. It is shaped such on the regular cylindrical part of its circumference that it does not form a clamping gap during the clamping of the ends of the packing. To clamp the ends of the packing, the clamping shaft is rotated by means of a tool into a predetermined angle of rotation position, in which it presses the ends of the packing against one of the gap ends of the cylinder channel, forming a clamping gap. Furthermore, two axial side walls of the channel, between which the clamping shaft is set movably, act as abutments for the clamping shaft.
Other clamping devices are known from DE 42 38 343 A1, U.S. Pat. No. 2,900,904, U.S. Pat. No. 5,485,785, DE 35 35 138 A1, DE 101 08 745 C1, DE 44 15 624 A1, DE 26 20 427 B2, and U.S. Pat. No. 4,577,560.